A curfew was imposed in the city following the incident, which led the Iranian government to demand a "firm response" from its Iraqi counterpart.
It marked the first violent turn for Hillah, where largely peaceful sit-ins have kept government offices and some schools closed. Demonstrators removed the Iranian flag and replaced it with an Iraqi one.
"The Iraqi government is responsible to secure safety of diplomatic missions and diplomats in Iraq ..."
The Iraq Foreign Ministry has condemned the attack on the Iran consulate, adding that the assault sought to harm relations between the two states. Reports said that staff at the consulate were able to evacuate the building before the protestors broke in. The bombings took place far from Baghdad's Tahrir Square, the epicenter of weeks of anti-government protests that have posed the biggest security challenge to Iraq since the defeat of IS.
Medics in Nasiriyah said they had to carry out more than 80 life-saving surgeries in hospitals crowded with casualties.
Iran-backed Iraqi Shia militias have reportedly been increasingly involved in assisting security forces in putting down the popular unrest which has swept the country - by some accounts even deploying snipers.
Activists on social media put out calls for locals to donate to blood banks to help the injured.
Protesters say they remain determined to bring down the government of Prime Minister Adel Abdul-Mahdi, who has unsuccessfully attempted to mollify them with concessions such as new elections and increased public subsidies.
The demonstrations escalated and spread across the country after security personnel responded with deadly force.
"We will cut the hand of anyone trying to get near (Grand Ayatollah Ali) al-Sistani", commander Abu Mahdi al-Muhandis said in a statement on the PMF website.
In the wake of the violence Amnesty International is urging Iraqi authorities to urgently rein in security forces.
Iraq's big and largely peaceful protests would be the most complicated challenge to some Shi'ite Muslim-dominated ruling class which has dominated state associations and patronage networks as a 2003 USA -led invasion toppled Sunni dictator Saddam Hussein. Protesters are mostly unemployed and disenfranchised Shiite youth seeking the departure of those claiming to represent them.
On Thursday, clashes flared near Karbala's provincial headquarters between some 200 protesters and riot police using tear gas and flash bangs.
Demonstrators retaliated by setting a police station on fire.
The footage could not be independently verified by MEE.
At least 350 people have been killed and thousands wounded since the start of the protest in Iraq on 1 October.
In Iraq's southern oil funding of Basra, demonstrators prevented government workers from getting to work by installing concrete obstacles painted as mock-up coffins of relatives killed in months of unrest, a Reuters witness said.
Demonstrators across Iraq have blamed powerful eastern neighbour Iran for propping up the Baghdad government.
Another protester, Ali, described the attack on the consulate as "a fearless act and a reaction from the Iraqi people".
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